Microclimate Temperature Research Articles

Effects of bedroom environment on average heart rate during sleep in temperate regions: Winter conditions in healthy males in their twenties with average BMI

The nocturnal average heart rate correlates more strongly with mortality rates than the resting heart rate or 24-hour average heart rate. Additionally, it has been suggested that as the average heart rate decreases, SDNN increases, indicating favorable autonomic function. This study aimed to identify the environmental factors that most significantly affect the day-to-day variability of average heart rate during sleep (SHR) in winter. Measurements were conducted in the participants' usual bedrooms of nine healthy male participants in their twenties with an average BMI, living in a temperate region. The measurement periods were from December 1, 2022, to March 8, 2023, and from December 1, 2023, to February 6, 2024. In addition to the heart rate, body movement, room, radiant, and bed microclimate temperatures, carbon dioxide concentration, relative humidity, and illuminance were measured. The results demonstrated that, when comparing across participants, the average room and radiant temperatures during the measurement period had a significant negative correlation with the average SHR during the measurement period, with correlation coefficients of −0.83 and −0.91, respectively. Using a multilevel structural equation model, no valid model was obtained at the between level, which examined differences between participants, while a valid model was found at the within level, which examined differences within participants. At the within level, the most explanatory factors for SHR were body movement, operative temperature, bed microclimate temperature, carbon dioxide concentration, and the interaction term between the bed microclimate temperature and carbon dioxide concentration. Overall, a deeper understanding of the impact of environmental conditions on average sleep heart rate could facilitate the design of environments favorable for autonomic nervous system activity during sleep.

The affinity of vascular plants and bryophytes to forest microclimate buffering

Abstract With recent advances in technology and modelling, ecologists are increasingly advised to use microclimate, not the usual coarse scale macroclimate based on weather stations, to better reflect the proximal conditions that species experience. This is especially relevant in forest ecosystems, where natural disturbances and management create substantial heterogeneity in microclimates. Under dense canopies, species may experience buffered (less extreme) microclimate temperatures relative to macroclimate, as well as increased relative humidity, reduced light and wind. Focusing on understorey plants, we investigated species response curves to the buffering capacity of the canopy layer, measured as the log‐transformed slope parameter of the microclimate to macroclimate linear relationship. If lower or higher than zero, microclimate temperatures are buffered or amplified, respectively, relative to macroclimate. During leaf‐on conditions (July–September 2021), we measured hourly microclimate temperatures in 157 plots across three temperate deciduous forests with contrasted macroclimates. We used paired hourly macroclimate measurements from nearby weather stations to derive the slope parameter, quantifying microclimate buffering. We surveyed vascular plant and bryophyte communities in 400 m2 plots centred on our microclimate sensors. Species were classified into three groups of forest affinity: core specialists; edge specialists; and generalists. We fitted generalized linear mixed‐effects models, by forest affinity group and by species, to obtain logistic response curves of the probability of occurrence against microclimate buffering. The species' optimum was computed as the microclimate effect that maximizes the species' probability of presence. We found contrasted microclimate preferences: Most bryophytes as well as the vascular plants classified as forest core specialists had an optimum in microclimate buffering, while forest edge specialists and generalists among vascular plants had an optimum in microclimate amplification. As canopies undergo increased disturbance frequency and intensity, more generalists and less forest core specialists might thus be expected in understorey communities, especially for bryophytes. Synthesis. Understorey plants have a species‐specific affinity to the forest microclimate, which we quantify for the first time. The investigation of species response curves to microclimate processes—buffering or amplification—can improve our understanding of the ecology of understorey plants, and help us anticipate their redistribution under climate change.

An Analysis of the Physiological and Psychological Responses Elicited When Wearing an Aerogel Cold Protective Jacket in Airflow

This study evaluated the thermal physiological and psychological responses elicited when wearing cold protective jackets with aerogel fillings in two cold environments, one without air velocities and one with air velocities (2.3 m·s-1), at an air temperature of 10°C. The participants were five healthy young males. Measures were taken of physiological parameters, blood pressure (BP), heart rate (HR), core temperature, oxygen uptake (Vo2), and microclimate (temperature and humidity). The psychological parameters evaluated were thermal and wetness sensation. No differences were observed in systolic blood pressure, heart rate, and oxygen intake between the conditions. At tympanic temperature, a significant difference was observed between the conditions during exercise (p <.05); . A significant difference was observed in the microclimate temperature of the clothing according to the airflow, and temperature changes in the chest and back revealed different patterns. Significant differences were observed in thermal sensation (whole body (p <.05), chest (p <.05), back (p <.01)) between airflow conditions. The results therefore indicate that cold protective jackets with an aerogel filling are suitable for people operating in low-temperature and airflow environments.

Comparison of the Time-Course and Magnitude of Cardiorespiratory Responses to Superimposed Surgical Masks or N95 Respirators during 20-min Treadmill Walking

Wearing medical barriers has recently expanded from healthcare to public settings, and could increase dead space and facilitate rebreathing of expired air resulting in heat accumulation, hypercapnia, and hypoxia, particularly during physical activity. We recently showed that participants wearing surgical masks (SM) and N95 respirators (N95) over 60-min during seated rest had mild and immediately reversible (a) increases face microclimate temperature, (b) increases in the pressure of end-tidal (PET)CO2, (c) decreases in PETO2, but (d) no differences in peripheral oxygen saturation (SpO2). Previous publications showed conflicting results of superimposed barrier wearing during physical activity, and there are limited studies that assessed face microclimate temperature and end-tidal gases, particularly comparing superimposed SM and N95. We hypothesized that participants wearing SM and N95 will experience mild face microclimate hyperthermia, hypoxia, and hypercapnia during 3mph treadmill walking. Participants (n=18; 8F) randomly wore (a) no barrier (NB), (b) SM or (c) N95 during a 10-min standing baseline, 20-min treadmill walking (3 mph), and a 10-min standing recovery. We continuously measured face microclimate temperature (thermistor), end tidal gases (PETCO2, PETO2; oro-nasal cannula), SpO2 (peripheral pulse oximeter). Average 20-min PETCO2 (higher; p<0.0001, P=0.0001) and PETO2 (lower; P=0.0003, P=0.0178) were significantly from baseline for both SM and N95, respectively. The delta between the 20-min average compared to the baseline data was not statistically significant for PETCO2 or PETO2 in all three conditions, except for ΔPETCO2 NB vs. N95 (higher; P=0.0344). Additionally, there was no difference in SpO2 across all barrier conditions during exercise. These mild physiological effects may account for qualitative reports of shortness of breath and increased perceived exertion while wearing barriers during physical activity. However, these effect-magnitudes are not physiologically-meaningful, and are immediately reversed upon cessation of exercise and/or barrier removal. NSERC. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Plant traits, microclimate temperature and humidity: A research agenda for advancing nature‐based solutions to a warming and drying climate

Abstract Climate models predict at least another 1.5°C warming in the next 75 years. This warming drives increased atmospheric drying and a global increase in the severity and duration of ecological drought. Vegetation has the capacity to reduce microclimate temperatures and atmospheric aridity. All species of plants create shade, move water, evapotranspire, humidify the air around them, and affect the temperature and vapour pressure deficit of the environment. Vegetation can thus act as a nature‐based solution to warming and atmospheric drying. These microclimate modifications likely depend on the traits, functional groups and diversity of the plant community. Vegetative feedbacks on microclimate are strong enough to buffer some plants against the negative impacts of warming and drying (e.g. facilitation). Synthesis: Here we present, for the first time, a trait‐based framework that can be applied across study systems for assessing microclimate temperature and humidity under vegetation. This framework includes multiple new hypotheses for future work in this area. We emphasize that a systematic examination of trait–microclimate relationships will enable us to use vegetation as a nature‐based solution to warming and atmospheric drying in a changing climate.

Research on the influence of solar radiation fuzzy adaptive system on the wet and hot environment in greenhouse

Chinese solar greenhouse (CSG) is an artificially constructed agricultural facility that provides a suitable environment for crop growth. However, the imbalanced temperature and humidity phenomenon occurring in greenhouse during summer greatly affects crop yield. This article proposes the application of solar radiation fuzzy adaptive system in greenhouse to address this issue. The design process includes hardware and algorithm design. The hardware part involves designing the travel distance of the curtain machine and the film winding machine, laying out the temperature and humidity sensors, and designing the control cabinet. The algorithm is optimized based on fuzzy control theory, data acquisition module consists of temperature and humidity sensors, executive components include the curtain machine and the film winding machine, and the data transmission, storage and feedback module consists of the control cabinet and the cloud-based database. These form an adaptive system, which will be subjected to a 10-day comparative experiment. The experimental results showed that in region 3, the peak value of temperature reduction in the third layer during the daytime was 26.2 °C, and the humidity increased by a maximum of 31.5 %. In region 2, the temperature increased by a maximum of 4.2 °C during the nighttime in the second layer, and the humidity decreased by 4.1 °C. Introduction of adaptive systems can play an important role in maintaining microclimate temperature and humidity in summer.

Cascading impacts of overstory structure in managed forests on understory structure, microclimate conditions, and Ixodes scapularis (Acari: Ixodidae) densities.

Forest management practices designed to meet varied landowner objectives affect wildlife habitat and may interrupt the life-cycle stages of disease vectors, including the black-legged tick, Ixodes scapularis Say (Acari: Ixodidae). Ixodes scapularis transmits multiple pathogens including Borrelia burgdorferi, the causative agent of Lyme disease, which is the most common tick-borne disease in the United States. There is evidence that a range of active forest management practices (e.g., invasive plant removal, prescribed burning) can alter tick densities and pathogen transmission. However, few studies have investigated relationships between forest stand structural variables commonly manipulated by timber harvesting and tick ecology. Foresters may harvest timber to create certain forest structural conditions like the mean number of trees, or basal area, per hectare. This study used a spatially replicated experiment in a blocked design to compare forest stands with a range of overstory structures and document variations in the midstory, understory, and forest floor, as well as microclimate conditions within tick off-host habitat. Greater numbers of trees or basal area per hectare correlated with greater canopy closure but less understory cover, stabilized microclimate temperature, higher microclimate humidity, and greater I. scapularis nymph densities. A random forest model identified understory forest structure as the strongest predictor of nymph densities. There was no relationship between the number of trees or basal area per hectare and daily deer (Odocoileus virginianus Zimmermann) activity or nymphal infection prevalence. These findings provide a deeper understanding of tick-habitat associations within a forest stand and have the potential to inform forest management decisions.

Impact of climate change on temperature variations and extrinsic incubation period of malaria parasites in Chennai, India: implications for its disease transmission potential

BackgroundThe global temperature has significantly risen in the past century. Studies have indicated that higher temperature intensifies malaria transmission in tropical and temperate countries. Temperature fluctuations will have a potential impact on parasite development in the vector Anopheles mosquito.MethodsYear-long microclimate temperatures were recorded from a malaria-endemic area, Chennai, India, from September 2021 to August 2022. HOBO data loggers were placed in different vector resting sites including indoor and outdoor roof types. Downloaded temperatures were categorised by season, and the mean temperature was compared with data from the same study area recorded from November 2012 to October 2013. The extrinsic incubation period for Plasmodium falciparum and P. vivax was calculated from longitudinal temperatures recorded during both periods. Vector surveillance was also carried out in the area during the summer season.ResultsIn general, temperature and daily temperature range (DTR) have increased significantly compared to the 2012–2013 data, especially the DTR of indoor asbestos structures, from 4.30 ℃ to 12.62 ℃ in 2021–2022, unlike the marginal increase observed in thatched and concrete structures. Likewise, the average DTR of outdoor asbestos structures increased from 5.02 ℃ (2012–2013) to 8.76 ℃ (2021–2022) although the increase was marginal in thatched structures and, surprisingly, showed no such changes in concrete structures. The key finding of the extrinsic incubation period (EIP) is that a decreasing trend was observed in 2021–2022 compared to 2012–2013, mainly in indoor asbestos structures from 7.01 to 6.35 days, which negatively correlated with the current observation of an increase in temperature. Vector surveillance undertaken in the summer season revealed the presence of Anopheles breeding in various habitats. Anopheles stephensi could be collected using CDC light traps along with other mosquito species.ConclusionThe microclimate temperature has increased significantly over the years, and mosquitoes are gradually adapting to this rising temperature. Temperature negatively correlates with the extrinsic incubation period of the parasite. As the temperature increases, the development of the parasite in An. stephensi will be faster because of a decrease in EIP, thus requiring relatively fewer days, posing a risk for disease transmission and a hindrance to malaria elimination efforts.Graphical

Macroclimate and canopy characteristics regulate forest understory microclimatic temperature offsets across China

AbstractForest microclimates can contrast substantially from the macroclimate outside forests. These microclimates regulate understory biodiversity and ecosystem functions. Studies have quantified the global patterns and driving factors of forest understory temperature offsets, but data from China were almost missing, making the global assessment incomplete. To fill this knowledge gap, we quantitatively synthesized 494 paired observations from China extracted from 91 publications to quantify mean (Tmean), maximum (Tmax) and minimum temperature offsets (Tmin). Results showed that (1) forest canopies significantly buffered understory Tmean and Tmax against macroclimatic temperature, with average offsets of 1.0 and 1.5°C, respectively, while understory Tmin offsets were not significantly different from zero; (2) forest type (broadleaved, mixed, vs. coniferous) and forest location (rural vs. urban) did not affect Tmean, Tmax or Tmin offsets, but climate zone and season showed significant impacts; and (3) macroclimatic temperature, wind speed, tree height and canopy density also impacted temperature offsets, although their effects varied among Tmean, Tmax and Tmin. Our results complement the global assessment of forest buffering capacity, and reiterate the necessity for incorporating microclimatic variability into future bioclimatic modelling of species demography and distributions.

Ecological indicator values of understorey plants perform poorly to infer forest microclimate temperature

AbstractQuestionEcological indicator values (EIVs) reflect species‘ optimal conditions on an environmental gradient, such as temperature. Averaged over a community, they are used to quantify thermophilization stemming from climate change, i.e. the reshuffling of communities toward more warm‐adapted species. In forests, understorey plant communities do not keep up with global warming and accumulate a climatic debt. Although the causes are still debated, this thermal lag may be partly explained by forest microclimate buffering. For the first time, we test whether community means of EIVs are able to capture microclimate (here, under forest canopies) temperature across, or also within forests.Location157 forest plots across three French deciduous forests covering a large macroclimatic gradient.MethodsTo assess whether EIVs can be used to infer the mean and range of microclimate temperature in forests, we measured understorey air temperature for ca. 1 year (10 months) with sensors located 1 m above the ground. We surveyed bryophytes and vascular plants within 400‐m2 plots, and computed floristic temperature from ordinal‐scale EIVs (Ellenberg, Julve) and degree‐scale EIVs (ClimPlant, Bryophytes of Europe Traits) for both temperature and continentality, i.e. temperature annual range. Finally, we fitted linear models to assess whether EIVs could explain the mean and range of microclimate temperature in forests.ResultsVascular plant and bryophyte communities successfully reflected differences in mean annual temperatures across forests but largely failed to do so for microclimate variation within forests. Bryophytes did not perform better than vascular plants to infer microclimate conditions. The annual range of microclimate temperatures was poorly associated with ordinal‐scale EIVs for continentality but was positively correlated with degree‐scale EIVs for annual range within lowland forests, especially for vascular plant communities.ConclusionOverall, the capabilities of EIVs to infer microclimate was inconsistent. Refined EIVs for temperature are needed to capture forest microclimates experienced by understorey species.

The Analysis of Lawn Rebate Programs and Drought Tolerant Lawn Recommendations in California

California faces persistent cyclical droughts that are expected to worsen due to climate change. The state currently operates in an overall annual water deficit, and projections suggest a 10% reduction in water availability by 2040. To combat these water shortages, Governor Newsom's administration has unveiled a water supply strategy with substantial investments in water conservation policies, including rebate initiatives to encourage residents to replace lawns with drought-tolerant (DT) plants and non-living hardscapes. However, questions have arisen about the overall effectiveness and environmental impact of these costly programs. This study delves into the potential consequences of replacing living lawns with non-living hardscapes, specifically whether it might elevate local microclimate temperatures, akin to urban heat islands (UHI) caused by the substitution of natural land cover with man-made, impermeable surfaces. The research examines existing rebate programs across the state, assessing their reimbursement structures and variations. Surface temperatures of commonly recommended lawn alternatives are measured and compared, including comparisons between different alternatives and drought-tolerant ground cover plants. Additionally, the study includes an experiment involving a drought-tolerant ground cover seed mix to replace a traditional lawn. The findings indicate that hardscape lawn alternatives generate significantly higher temperatures than any of the drought-tolerant ground cover plants analyzed. Furthermore, there is notable temperature variability among the hardscapes studied. Consequently, this paper proposes modifications to the existing rebate programs and emphasizes the importance of ensuring that environmental solutions introduced to address one issue do not inadvertently exacerbate related problems.

Analysis of microclimate temperature and relative humidity distribution of local poultry house in a subtropical area of Nigeria

The design of the ventilation system to ensure microclimate condition are optimum in poultry houses in the Nigerian context requires knowledge of the microclimate parameter distribution, which is lacking in the literature. This study investigated the patterns of temperature and RH distributions in a typical local poultry house. The specific objectives were to (i) analyse the vertical and horizontal distributions of the microclimate parameters in battery cage poultry housing and deep litter poultry housing, (ii) identify whether the distribution is homogenous or heterogeneous, and (iii) identify the data spread of parameters. An experimental intensive naturally ventilated local poultry house was used for this study. It consisted of deep litter (DL) and battery cage (BC) poultry housing systems partitioned by an air wall. Daytime, nighttime, rainy, and dry season temperature and RH distributions in the BC and DL poultry housing were analysed. Approximately 1.2 °C temperature difference was recorded between the poultry house and the ambient environment during the day and night. The temperature and RH distributions in the poultry housing were heterogeneous. Approximately 5% and 67%–73% of the daytime and nighttime temperature data, respectively, and 37%–41% of daytime RH fell within the optimum values.

The functional microclimate of an urban arthropod pest: Urban heat island temperatures in webs of the western black widow spider

Urbanization alters natural landscapes and creates unique challenges for urban wildlife. Similarly, the Urban Heat Island (UHI) effect can produce significantly elevated temperatures in urban areas, and we have a relatively poor understanding of how this will impact urban biodiversity. In particular, most studies quantify the UHI using broad-scale climate data rather than assessing microclimate temperatures actually experienced by organisms. In addition, studies often fail to address spatial and temporal complexities of the UHI. Here we examine the thermal microclimate and UHI experienced in the web of Western black widow spiders (Latrodectus hesperus), a medically-important, superabundant urban pest species found in cities across the Western region of North America. We do this using replicate urban and desert populations across an entire year to account for seasonal variation in the UHI, both within and between habitats. Our findings reveal a strong nighttime, but no daytime, UHI effect, with urban spider webs being 2–5 °C warmer than desert webs at night. This UHI effect is most prominent during the spring and least prominent in winter, suggesting that the UHI need not be most pronounced when temperatures are most elevated. Urban web temperatures varied among urban sites in the daytime, whereas desert web temperatures varied among desert sites in the nighttime. Finally, web temperature was significantly positively correlated with a spider's boldness, but showed no relationship with voracity towards prey, web size, or body condition. Understanding the complexities of each organism's thermal challenges, the “functional microclimate”, is crucial for predicting the impacts of urbanization and climate change on urban biodiversity and ecosystem functioning.

Microclimate mapping using novel radiative transfer modelling

Abstract. Climate data matching the scales at which organisms experience climatic conditions are often missing. Yet, such data on microclimatic conditions are required to better understand climate change impacts on biodiversity and ecosystem functioning. Here we combine a network of microclimate temperature measurements across different habitats and vertical heights with a novel radiative transfer model to map daily temperatures during the vegetation period at 10 m spatial resolution across Switzerland. Our results reveal strong horizontal and vertical variability in microclimate temperature, particularly for maximum temperatures at 5 cm above the ground and within the topsoil. Compared to macroclimate conditions as measured by weather stations outside forests, diurnal air and topsoil temperature ranges inside forests were reduced by up to 3.0 and 7.8 ∘C, respectively, while below trees outside forests, e.g. in hedges and below solitary trees, this buffering effect was 1.8 and 7.2 ∘C, respectively. We also found that, in open grasslands, maximum temperatures at 5 cm above ground are, on average, 3.4 ∘C warmer than those of the macroclimate, suggesting that, in such habitats, heat exposure close to the ground is often underestimated when using macroclimatic data. Spatial interpolation was achieved by using a hybrid approach based on linear mixed-effect models with input from detailed radiation estimates from radiative transfer models that account for topographic and vegetation shading, as well as other predictor variables related to the macroclimate, topography, and vegetation height. After accounting for macroclimate effects, microclimate patterns were primarily driven by radiation, with particularly strong effects on maximum temperatures. Results from spatial block cross-validation revealed predictive accuracies as measured by root mean squared errors ranging from 1.18 to 3.43 ∘C, with minimum temperatures being predicted more accurately overall than maximum temperatures. The microclimate-mapping methodology presented here enables a biologically relevant perspective when analysing climate–species interactions, which is expected to lead to a better understanding of biotic and ecosystem responses to climate and land use change.

DEEPURBANMODELLER (DUM): A PROCESS-INFORMED NEURAL ARCHITECTURE FOR HIGH-PRECISION URBAN SURFACE TEMPERATURE PREDICTION

Abstract. High-resoulution downscaling of surface climate metrics like urban surface temperature, is a crucial and ongoing research challenge in urban climatology and environmental studies. In this study we propose a groundbreaking Physics-Inspired Neural Architecture for Modeling (PINAM) called DeepUrbanModeller(DUM), designed specifically for urban microclimate temperature estimation. DeepUrbanModeller(DUM) harnesses process-based modelling and satellite remote sensing, and draws upon high-accuracy 3D point clouds to deliver precise estimations of urban Land Surface Temperature (LST) at ultra-high resolutions. By incorporating high-accuracy land surface geometric data sourced from 3D point clouds and guided by the principles of atmospheric physics linked to surface temperature, DeepUrbanModeller(DUM) creates a data-driven framework, informed by physical laws, to accurately model high-resolution temperature distributions a task challenging for numerical simulations or conventional machine learning. The DeepUrbanModeller(DUM) design integrates two key components: Global Physical Feature Interpretation (GPFI) and Local Urban Surface Insight (LUSI). The GPFI captures broader urban physical parameters, ensuring the estimates comply with relevant physical laws. The LUSI enhances estimation performance at high-resolution levels by utilizing a newly proposed Urban Detail Orientation Index (UDOI) derived from 3D point clouds. Experimental results demonstrate the DeepUrbanModeller(DUM)’s superior capability in estimating urban LST on a detailed 30-by-30 meter grid, achieving an estimation error of less than 0.2 Kelvin compared to satellite measurements, a performance surpassing traditional methodologies.

The vitality of native grassland plants in current urban climatic conditions in Gauteng, South Africa

Plants are essential components of urban microclimates, as they can help mitigate some of the adverse effects of urbanisation, enhance environmental quality, and thus contribute to overall species well-being and the sustainability of cities. Urban planners and policymakers often incorporate green infrastructure and urban greening into their strategies to create healthier and more livable urban environments. Plants are primary producers, serving as a baseline for the attraction and habitat of other species; they also provide vital ecosystem services, such as climate amelioration. Landscape designers and horticulturalists can influence plant selection through built environment interventions, increasing urban ecosystem services and benefits. Based on the evidence of native plant preferences by insects and people and their natural adaptation to regional climatic extremes, we tested, through an experimental study, the potential of native grassland plants to survive in assemblages in current urban environments. The study specifically monitored the tolerance of nine native grassland plant species to urban environments over six months in Gauteng, South Africa. A stratified random sampling was done by monitoring permanent quadrats in two purposefully engineered urban native gardens. Plant vitality was evaluated using chlorophyll a fluorescence. General climate data were obtained from a local weather station. Microclimatic temperature and humidity data were collected at each site and quadrat using Hygrochron High-Resolution Temperature and Humidity data loggers. The results indicated that all nine native plant species functioned with good photosynthetic health and can be recommended as resilient species that tolerate current urban conditions. Correlation studies indicated that two forb species, Haplocarpha lyrata and Scabiosa columbaria, showed great tolerance to current urban conditions. This vitality is likely contributed to their winter dormancy morphologically based on below-ground biomass, and their physiological adaptation to tolerate both wet and dry habitat conditions. This points to the potential of grassland forb species for urban use and the potential for climate adaptation in grassland areas.

Higher soil moisture increases microclimate temperature buffering in temperate broadleaf forests

Forest canopies can buffer the understory against temperature extremes, often creating cooler microclimates during warm summer days compared to temperatures outside the forest. The buffering of maximum temperatures in the understory results from a combination of canopy shading and air cooling through soil water evaporation and plant transpiration. Therefore, buffering capacity of forests depends on canopy cover and soil moisture content, which are increasingly affected by more frequent and severe canopy disturbances and soil droughts. The extent to which this buffering will be maintained in future conditions is unclear due to the lack of understanding about the relationship between soil moisture and air temperature buffering in interaction with canopy cover and topographic settings. We explored how soil moisture variability affects temperature offsets between outside and inside the forest on a daily basis, using temperature and soil moisture data from 54 sites in temperate broadleaf forests in Central Europe over four climatically different summer seasons. Daily maximum temperatures in forest understories were on average 2 °C cooler than outside temperatures. The buffering of understory temperatures was more effective when soil moisture was higher, and the offsets were more sensitive to soil moisture on sites with drier soils and on sun-exposed slopes with high topographic heat load. Based on these results, the soil–water limitation to forest temperature buffering will become more prevalent under future warmer conditions and will likely lead to changes in understory communities. Thus, our results highlight the urgent need to include soil moisture in models and predictions of forest microclimate, understory biodiversity and tree regeneration, to provide a more precise estimate of the effects of climate change.

Seasonal roost selection of wild turkeys at their northern range edge

Wild turkeys Meleagris gallopavo are diurnally active birds that spend the dark hours roosting in trees. We tested the hypothesis that multiple benefits exist for roost tree selection by wild turkeys, including thermoregulation, resource acquisition, and protection from predators. We compared 48 roost trees used by eastern wild turkeys M. g. silvestris in Ontario, Canada to 48 non‐roost trees sampled contemporaneously during 2017–2019 to determine roost site selection between seasons. Mean (± SE) roost tree height (21.4 ± 0.8 m) was taller than non‐roost trees (18.2 ± 0.8 m), and roost trees were also larger in diameter at breast height (58.1 ± 5.5 vs 38.7 ± 3.1 cm). Using ibuttons to collect microclimate temperatures at the tree, we found that mean temperature (± SE) of a deciduous roost (14.5 ± 0.1°C) was higher than temperature at either a coniferous roost (13.9 ± 0.1°C) or ambient temperature (13.2 ± 0.1°C) during the summer months. In winter however, we did not find any relationship between temperature and tree type. Roosts were closer to buildings (150.8 ± 26.0 m) in the winter compared to summer and year‐round roosts, and winter roosts were also farther away from crops (395.2 ± 63.7 m) compared to roost sites used year‐round. Summer roosts were closer to roads (143 ± 36.3 m) than the roosts in the winter and roosts used year‐round. Our data suggest that thermoregulation is not the driving force behind roost selection; instead, predator avoidance appears to play the most important role, with some weaker evidence in support of proximity to resources.

Using airborne LiDAR to map forest microclimate temperature buffering or amplification

Mapping the microclimate effect of forest canopies on understory temperature requires spatially explicit predictors at very fine spatial resolutions. Light Detection And Ranging (LiDAR) offers promising prospects in that regard, as it allows capturing the vertical dimension of vegetation structure at a very high resolution over large areas.To explore the potential of airborne LiDAR-derived metrics to predict understory temperature, we focused on the forest of Blois (France), a 2740-ha lowland managed forest dominated by oak (Quercus petraea). We installed HOBO sensors measuring microclimate air temperature at one-metre height in 53 stands of contrasting vegetation structure, from open to very dense and from young regeneration to mature stages. Using a nearby weather station as the macroclimate temperature reference, we calculated the slope (log scale) coefficient of the linear regression between microclimate and macroclimate, as a simple parameter describing the microclimatic buffering (log(slope) < 0) or amplification (log(slope) > 0) capacity of the habitat.An airborne LiDAR flight was conducted during summer 2021, matching the timing of our temperature measurements. From the resulting 3D point cloud, three complementary metrics of forest structure were derived: the maximum height, the Plant Area Index and the Vertical Complexity Index. They were calculated for circular buffers of different radii (1 m to 100 m) centred on each HOBO sensor.We found that the 5-m radius combining the three metrics into a single multivariate model explained the greatest proportion of variance in the microclimate effect of each stand (R2 = 0.91). We mapped the buffering or amplification effect of vegetation structure on understory temperatures over the entire forest of Blois at a 10-m resolution. 91.4% of the surface of the forest was significantly buffered relative to macroclimate temperature, while 2.7% was amplified, especially in road verges, clear-cut and regeneration areas. Based on our simple linear model, we were able to derive understory air temperature maps for any temporal resolution (i.e. hourly, daily, or seasonal). The results highlight the great capacity of airborne LiDAR to retrieve forest structure parameters and generate high-resolution maps of the thermal environment.Applications for mapping the buffering or amplification of microclimate temperature are plentiful, especially in the context of climate change. They include improving the understanding of physiological processes such as thermoregulation or phenology, modelling the thermal connectivity of the landscape, improving species redistribution models, spotting microrefugia for conservation, informing forest management for tree regeneration or wildfire control, or even prioritising cooling recreational areas for humans to escape heatwaves in urban forests.

Is it getting hot in here? The effects of VR headset microclimate temperature on perceived thermal discomfort, VR sickness, and skin temperature

Thermal discomfort is a driver of negative user experiences with modern VR headsets since they are similar to head-worn gaming computers. Here, we examined the effect of microclimate temperature (MCT; i.e., the air between headset and user) and the effect of standing and seated use on thermal discomfort for a goggle style headset. Users played VR games across three 48-min sessions with different thermal profiles ranging between 28°–43 °C. Perceived thermal and weight discomfort were rated by participants every 12-min. Thermal, but not weight comfort declined during the study period as MCT increased. Users sweat more and had greater forehead temperatures while standing with the lowest thermal profile, suggesting thermal management is more critical for active experiences. Overall, this study recommends MCT should be kept below 36 °C. Finally design for thermal comfort should be tailored to the individual, experience duration and activity level.